Electric fuse



June 20, 1950 PARKER 2,511,872

' ELECTRIC FUSE Filed Jan. 27, 1948 2 Sheets-Sheet 1 Leland L Parker M wmfg z L. PARKER I ELECTRIC FUSE June 20, 1950 2 Sheets-Sheet 2 Filed Jan. 27, 1948 I Leland L Parker Patented June 20, 1950 U 1 TE ii (Granted under. the act of March 3, 1883-, as

amended April 30, 1928; 370- 0.. G. 757) The invention described herein may be manunism which makes it dificult' to secure good factured and used by or for the Government for operation; governmental purposes without the payment to It is an object of, my invention to secure accume of any royalty thereon. rate time arming (as against air travel arm- My invention relates to safety arming mecha- 5 ing) by theuse'of a clock work timingv mechanism nisms for fuzes and particularly to an arming driven from the high speed; turbine shaft, the mechanism for electrically actuated bomb iuzes, above mentioned-and other difficulties being obsaid arming mechanism having a time delay viated by the use of: a, slipping or a non-rigid mechanism adapted to control the time of armconnection between the turbine and; the timer. ing of said fuze. More specifically my invention This connection consists of a magnetic torque relates to means for utilizing a variable-force transmitting device between the driving: shaft driving source such as a wind vane to provide and the constant speed clock work so constructed the driving force for drivingan escapement mechthat if the shaft speed exceeds that of the driven anism to provide a definite controllable time delay initial clock work element there will be slippage for fuze me h i m, between the two. It is also an object to provide My invention is applicable to an projectile a novel means combining a wind van-edriven fuze of the mechanical or electrical type for generator-andamagnetictorque transmitting'dewhich safe operation requires that the projectile vice so that practically no extra space or materemain in the unarmed condition until a prerial is used over that normally used by the determined interval after it is released but the generator so that-in the case of anelectric fuze invention is particularly applicable to electrically of known type (for example a proximity fuze) actuated bomb fuzes in which an electric squib which normally'employs such a generator, the is fired to set oil the fuze, and my invention will mechanical power source for a time arming be disclosed in connection with such a fuze al-- mechanism is obtained at little or no cost in though it will be understood that it is equally space or weight. applicable to any other type of fuze employing Other objects are to provide a fuze arming a wind vane or turbine. mechanism that can be used with existing types So-called air trave arming has long been of :t'uze; and that is reliable and fool-proof used for projectile fuzes. In this type of device in operation.

a wind vane or turbine is so associated with the Other objects and advantages will be apparent arming device that after a predetermined number from the following description and drawings in of turns of the wind vane due to travel of the which? projectile through the air, the fuze is in the Figure 1 is a' longitudinal cross-sectional view armed condition. One important objection to of a projectile embodying my invention, in'the this type of arming is that the time required to unarmed state,

complete the arming depends on the velocity of Figure 2' is "an enlarged sectional view similar the projectile during the arming, and this is to Figure 1 of the clock work' mechanism, shown diiierent for different sizes and types of projecin the armed position,

tiles such as bombs and rockets. As it is desirable Figure 3- is a sectional view taken; on line3=3 to use one type of fuze for more than one type 40 of Figure 1,

or size of projectile, it wil'l be seen that the arm- Figure 4 isa sectional. view taken onv line- 44 ing time is not necessarilya definite quantity of Figure 1,- Y when air travel type of arming is? employed. The Figure 5-is a sectionahviewtaken on line- 5-5 arming time with this type of device will also of Figure 1 showing the rotor in the unarmed vary with the horizontal initial speed of the position projectile, which is undesirable; It has there- In the drawing-s, referencenumeral l reprefore been proposed to use a spring driven clock sents the forward end of a. projectile such as a mechanism, and such mechanisms have been debomb. rocket, etc., having. a. fuze' 2: in the nose veloped but they lack the essential safety'of air thereof. This fu-ze is provided. with awind-vane travel mechanisms in that. they may operate if or turbine 3- for-driving; a shaft. 4 which passes accidentally started even when the projectile is through. a chamber Swhiehhouses the operative not in flight. elements of the fuze.

Drivinga clock mechanism directly from a wind My invention is particularly applicable to el'ecvane shaft does not. always supply a suificiently 1 tric fuzes requiring electric power, such as-proxuniform torque to the clock mechanism since the imity fuzes although it is not limited to; any'parwind vane speed may vary widely so that it is ticular type of fume, and the electric components diflicul-t to obtain the desired; accuracy oftirning; and other working elements of the fuze may be moreover the direction operation-of slow speed housed in chamber 5. Shaft 4r rotates in bear clock work from a high speedshaft through ingslaxandtlrand hasfastened' at its free end gearing results inlarge forces on the clock mecha- 69 rotor 6 which is a strongly permanently mag- 3 netized rotor of highly retentive material such as for example that known in the trade "Alnico, so magnetized as to provide a number of alternate north and south poles. The rotor B is surrounded by a number of salient projecting paramagnetic stator members I and 8 alternately disposed as shown in Figures 1 and 4 of which members I are associated with one end of winding 9, and members 8 are associated with the other end of winding 9, the two ends being joined by a paramagnetic spool or core member 10. It will be seen that rotation of rotor 6 produces a rotating magnetic field which sweeps past stator members '1 and 8 to induce an alternating E. M. F. in stator winding member 9 which thus serves as a generator. The ends of coil 9 are connected by leads I I. and I2 respectively, to slip rings [3 and I4, respectively, mounted on casing l5. This casing is firmly fastened to the stator and tortubular casing sleeve 2| so that these elements all move as aunit, with shaft 4 and rotor 6 free to rotate with respect to this unit which in turn is free to rotate in bearings l8 and I9, while conducting'current to thefuze circuit (to be later described) through stationar brushes IE or I! in contact I with'slip rings l3 and M respectively. r v

Fastened to sleeve 2| for rotation therewith is gear 22, which'drives the clock workgenerally indicated by numeral 23 in Figural. Gear 24 of this clock work is fastened to escapement wheel 25 which drives pallet 26 to form an escapement for limiting the speed of the clock worksystein. The assembly of gear 24 and wheel 25 is itself internally threaded to cooperate with the threaded portion of a rod 28 as shown in-Figures land 2. In the initial position of'the arming mechanism rod 28 extends into a hole 32 in rotor 33, passing through supporting member 3|. Rod 28 is keyed-to member3l=by a key 29 so that it can freely slide longitudinally with respect to 3 I but can not rotate with respect thereto. Rotation of gear' 24 is'therefore efiectiveto withdraw rod 28 from rotor 33. This rotor carries a squib 34 having external contacts mountedon the rotor and is urged toward rotation by spiral spring 31 but restrained by rod 28. Whenthe 'rod is withdrawn from hole 32 spring 3l rotates the rotor 33 180 into the armedpositio'n where it is aligned with booster lead 44 and where contacts 35 engage stator contacts 4! so that the squib 34 is in circuit through leads 32 with the generator and the electric fuze elements in chamber 4. Rotor 33 is stopped in this position-by pin 38 moving in arcu'ate slot 39 until'it is stopped by member 3| from further rotation. w

' The operation of the system shown should now be apparent. Arming wire 49 is pulled whenthe projectileis released. The shaft 'j l 'imm'e'diately begins to rotate as' the projectile moves'through the air driving rotor 6 at high speed and generating "an E MLF. in winding}. This produces also a; reaction torque on the stator and hence on casing 15 which tends't'o drive the casing in the same direction (but 'atafslow er speed). This motion is'tr'ansmitted bycasingigear 22 to clock work gear 24 to drivethe clockwork and at the same time to withdraw the rod '28 from the initial safe position shown'in Figure {1 into the final position shown'finFigur'e 2, whenthe rod is out of engagement with rotor 33, enabling the latter to rotate from the'safe position into the armed position. Subsequent closing of the squib cir-' cuit by the electric'i'uze elements in chamber 5 can now de'tonatethe squib to explode the projectile. The time required to release the rotor for rotation is determined by the constants of the clockwork and the physical parameters of the system and is fixed in the system shown; but it will be obvious that time regulating means may be incorporated if desired so that the time will be varied as required. This may also accomplish by varying the length of rod 28 which is engaged with rotor 33 or by using a standard clock escapement movement with a spring loaded balance wheel and varying the spring loading, or in any desired known manner.

It will be seen that the above described construction accomplishes the objects of the invention but it will be apparent that other mechanical motions and elements than the ones shown could be used to accomplish the same objects within the scope of the invention as shown in the appended claims.

I claim; I

1. In combination, a fluid driven turbine, a shaft driven thereby, a substantially constant speed rotating system driven by said shaft, and a slipping connection between said shaft and said system, said slipping connection comprising a magnetic coupling, said magnetic coupling comprising a generator having a rotating field member driven by said shaft and an armature member free to rotate about the same axis of rotation as said field member and mechanically coupled to said constant speedrotating system.

2. An arming system for an'electric fuze comp si g a wind vane in the nose of said fuze, a shaft driven by said wind vane, a clockwork timer driven by said shaft, a slipping connection between said timer and said shaft, a powder train interrupter actuated to arming position by said clockwork, a latch for retaining said interrupter initially in said safe position, spring means biasing said interrupter into armed position and means actuated by said timer for releasing said latch from said retaining position after a predetermined time of operation of saidtimer, said slipping connection being a magnetic coupling device and including a generator having a rotating field member driven by said shaft and an armature free to rotate about the same axis of rotation as said field member and mechanically coupled to said clockwork timer.

3. The invention recited in claim 2 and including sliprings on said armature member, leads from the armature winding to said sliprings, and stationary external brushes bearing on said sliprings. I

4. The invention recited in claim 2 and including a squib on said powder train interrupter, squib contacts on said interrupter, and circuit connections including said generator, said squib and said electric" fuze.

' "LELAND L.PAR,KER.

"REFERENCES. orr'En The following references are of record in th 5 file of this patent:

V UNITED STATES PATENTS 257.335 Great Britain Aug. 27, 1926 

